Comparison of the antibacterial effect of silver and zinc oxide in solution and on coated surfaces

The occurrence of antibiotic resistance of pathogens is a continuing problem for the health care industry. At least 70% of Hospital Acquired Infections (HAIs) are known to be resistant to a minimum of one or two of the most commonly used antibiotics.

Recent advances in pharmaceutical nanotechnology have demonstrated that metal nanoparticles such as titanium dioxide (TiO2), zinc oxide (ZnO), silver (Ag) and copper oxide (CuO) have promising antibacterial properties. Staphylococcus aureus and Pseudomonas aeruginosa are among the two most common organisms responsible for nosocomial infections, both of which exert antibiotic resistance.

It is of paramount importance that novel alternatives to antibiotics are discovered to prevent antibiotic resistance in HAIs. In this work it was found that greater reductions of biofilms were observed when treated with a nanoparticle solution after formation than when preventing biofilm formation using a coated surface. This may be due to Zn+ and Ag + ions being released slowly from the surface into the media in comparison to metal solutions, where the biofilms are being exposed to an instant maximum dose. The metal solutions therefore provide a greater antimicrobial effect.